Michelle Obama welcomed the 2013 holidays into the White House this week with military families, hot cider, hand-decorated cookies, a 136kg gingerbread White House and an extremely friendly new family pet.

Sunny, the 1-year-old Portuguese water dog the Obamas got over the summer, bounded into a State Dining Room full of children dressed in sparkly shoes and lacy dresses and headed right for little Ashtyn Gardner, 2, from Mobile, Alabama. All of a sudden the blond girl with ringlet curls, whose parents are both in the Navy, was down on the rug.

"Are you okay?" said a concerned Obama, mum-in-chief, tugging back on Sunny's leash.

There was no need for damage control as before Ashtyn could answer, she was back on her feet and Sunny was licking her face.

All seemed well again and the kids from military families could get back to frosting cookies and making paper poinsettia flowers with the first lady, crafty projects that have become a part of the Obama holiday traditions.

In this, the Obamas' fifth holiday season at the White House, the customs of Christmas past were observed with a few twists.

First, the preview was a party for military families, as it has been in the past. The theme this year for the White House holidays is "Gather Around: Stories of the Season," described as telling tales of the country's history and displaying decorations that reflect it.

There are art displays and Christmas trees made of repurposed books. (The 450 books used in the decorations will be donated to a local school's book drive after the holiday season.)

Many ornaments are recycled and reused. This year's additions included wooden frames holding silhouettes of landmarks such as Mount Rushmore and the Golden Gate Bridge.

The Blue Room tree, a 5.6 metre tall Douglas fir known as the official White House Christmas Tree, was laden with holiday greeting cards on which children living on military bases shared their favourite holiday traditions.

The colours of the ornaments and decorations on the 24 Christmas trees that line the public tour route are subdued, with lots of chocolate browns, pale blues and golds. Not only is there a gingerbread house, complete with chocolate versions of Bo - the Obamas' first Portuguese water dog - and Sunny, but it is sitting on more than 1200 Springerle cookies made into a custom-made hearth. The hearth is framed by sugar paste re-creations of the tiles commissioned for President Franklin Delano Roosevelt's fireplace, to evoke memories of his "fireside chats".

According to Bill Yosses, the White House executive pastry chef, this is the first year the gingerbread house has running water - a carpenter rigged up a functioning replica of the North Lawn fountain, to which blue food colouring was added.

Eighty-three volunteers worked for five days to decorate the White House. Donna Perry, a lawyer from Louisville, Kentucky, said it was her first time as a volunteer.

She was decorating the tree in the Blue Room when the president stopped by and was hugged by some excited volunteers who got glitter on his lapel.

At the start of the event, Michelle Obama addressed the military families in a gray-and-white dress and pearls.

"Now, over the course of this season, about 70,000 people will come to see our holiday decorations. Not bad," she said.

"And I can't imagine a better group of people than all of you to be our first guests." (About 13,000 of those 70,000 people will be attending official White House receptions and parties.)

Obama mentioned that while many families will be reading classics to their kids by the fire, some military personnel will be doing it a different way.

"I'm thinking about the thousands of men and women in uniform serving abroad who wake up in the middle of the night in some remote part of the world to read a special holiday story to their children over Skype," she said, calling it "new ways to make the season bright".

Before taking the children to make crafts with White House florists, bakers and pastry chefs, Obama warned parents: "I'm going to take your kids... and we're going to do some decorating."

She added: "I guarantee you we will not lose them, but I can't guarantee you they will come back clean."

She worked hard, though, to keep their party clothes from getting trashed.

When she saw a little girl at the cookie-decorating table drop some gooey stuff on her outfit, Obama did what all mums would do.

She whipped out a dish towel with a little water on it and tried to rub the goop out of the girl's glittery sweater.